Rheological behavior of a solution of particles aggregating on the containing walls

The possibility of macroscopic shear-thickening behavior is shown for a solution containing particles that tend to stick and grow aggregates on the walls containing the solution. A simple one-dimensional model is used with two basic ingredients: shear tends to peel off the aggregate and the viscosity of the solution increases with particle concentration. In addition to shear thickening, instabilities at fixed driving velocity can also occur. In cylindrical geometries it is even possible to reach situations displaying instabilities both at fixed stress (torque) and at fixed velocity.